To make room for Dempster on the 40-man roster, they designated RHP Pedro Beato for assignment.
Here's the full release from the Red Sox:
BOSTON, MA—The Boston Red Sox today signed right-handed pitcher Ryan Dempster to a two-year contract through the 2014 season. A two-time All-Star, Dempster has made at least 28 starts and has won at least 10 games in each of the last five seasons since returning to the starting rotation in 2008. His 3.74 ERA during that five-year stretch ranks 13th among Major Leaguers with at least 950.0 innings pitched.
To make room for Dempster on the 40-man roster, right-handed pitcher Pedro Beato was designated for assignment.
Dempster, 35, went 12-8 with a 3.38 ERA (65 ER/173.0 IP) and 153 strikeouts over 28 starts last season, his 15th year in the Major Leagues. He posted a 2.25 ERA (26 ER/104.0 IP) in 16 starts for the Chicago Cubs before being acquired by the Texas Rangers at the July 31 trade deadline.
At the time of the trade, Dempster ranked second in the National League in ERA and opponent batting average (.210), and was third with a 1.04 WHIP (min. 100.0 IP). He struck out 70 batters in 69.0 innings over 12 starts with Texas to place sixth among American League qualifiers with 9.1 strikeouts per nine innings beginning in August.
Dempster, who will wear No. 46, has posted an ERA of 3.85 or lower four times in the last five seasons. He has totaled a 65-49 record (.570) to go along with his 3.74 ERA in those five years and also ranks among Major League leaders with 160 starts (T-13th) and 911 strikeouts (14th) since 2008.
He has thrown at least 200 innings while making 30 or more starts seven times in his career, all since 2000. Only nine other hurlers have as many 200-inning/30-start campaigns in the last 13 years.
An All-Star with the Florida Marlins in 2000 and again with the Cubs in 2008, Dempster spent the first 14 ½ seasons of his career in the National League. In joining the Rangers last summer, he returned to the club that originally signed him as a third-round selection in the 1995 June draft.
He has made at least 10 appearances in the NL in each of his 15 Major League seasons, the only player to do that in every season since 1998. His 1,848 strikeouts as a National Leaguer rank second among active players, and he also places among active leaders with 117 wins (5th), 310 starts (4th), and 2,146.2 innings (4th) in the Senior Circuit.
Dempster has made 547 career big league appearances, including 322 starts, since his 1998 debut. He owns a career 124-124 record with a 4.33 ERA (1,067 ER/2,215.2 IP) and 1,918 strikeouts, pitching for the Marlins (1998-2002), Cincinnati Reds (2002-03), Cubs (2004-12), and Rangers (2012).
He served as the Cubs’ Opening Day starter each of the last two years and was the Marlins’ Opening Day starter in 2001 and 2002.
Primarily a starter in his Major League career, Dempster also racked up 87 saves over four seasons in the bullpen for the Cubs from 2004-07, serving as the club’s closer for three of those years (2005-07). He joins Derek Lowe as the only active pitchers with at least 100 career victories and 85 saves.
A native of British Columbia, he ranks second all-time among Canadian Major Leaguers in wins, starts, and innings, trailing only Hall of Famer Ferguson Jenkins in all three categories.
He has made two career postseason appearances, both with the Cubs, pitching out of the bullpen in 2007 and as a starter in 2008.
Throughout his career, Dempster has dedicated himself to charitable efforts. He was the Cubs nominee for the Roberto Clemente award in 2006, 2008, and 2011, which honors a player who combines outstanding skills on the field with devoted work in the community. Following the 2001 season, he was presented with the All Heart Award by the Florida chapter of the Baseball Writers’ Association of America for his community endeavors.
In 2009, he created the Dempster Family Foundation, which is dedicated to raising awareness of DiGeorge Syndrome, a birth defect due to the deletion of part of chromosome 22. The foundation reaches out to children that have this syndrome and to the charities that support them, and provides financial assistance to charities that aid and comfort critically ill children. Through the foundation, he has also supported youth baseball programs, military families, and animal shelters in the Chicagoland area.
Over his last seven seasons with the Cubs, he donated tickets to social service agencies that assist low-income children through his “Dempster’s Dugout” ticket program.
Beato, 26, made four relief appearances with Boston after being acquired from the New York Mets on August 16, going 1-0 with a 4.70 ERA (4 ER/7.2 IP) in those games. He also pitched in seven contests for Triple-A Pawtucket, including three during the International League postseason.